I'd wouldn't say the bulk comes from large stores vs. 'win-a-trip' type sites. Its both. I buy these leads on a regular basis (many millions a year) and I'd say

I'd wouldn't say the bulk comes from large stores vs. 'win-a-trip' type sites. Its both. I buy these leads on a regular basis (many millions a year) and I'd say where the most comes from depends on country primarily. Also businesses like Dominoes typically dont sell identifiable customer data, they will often present your company as an offer either via EDM, newsletter or ever increasingly post-transaction via lead aggregators. When Dominoes/Target type organisations do sell data it's typically done in a non-PII (personally identifiable information) format, for legal, ethical and brand reasons. This way companies can utilise the data do things like understand purchase personalities/habits by postcode type thing but they dont directly know who you are. There is another subset of companies that claim they can take this non-PII data and re-match it to people but I'm skeptical about how accurate this is. Another an area not mentioned of personal darta storage that is every growing is programmatic media. In this ad servers attempt to identify you and call on stored information which is then used in a stock market like real-time environment to bid for ad views. Like when ads follow you around the internet, but for every sophisticated information/algorithmic rationale on who you are. Nothing nefarious but marketers want to show ads that are likely to be interesting and result in a sale (or other company goal).